This article is about a plant genus. For the species in this genus that is widely used in herbal medicine, see Rhodiola rosea

Rhodiola rosea

Rhodiola rosea is a plant in the Crassulaceae family that grows in cold regions of the world. These include much of the Arctic, the mountains of Central Asia, the Rocky Mountains, and mountainous parts of Europe, such as the Alps, Pyrenees, Carpathian Mountains, Scandinavia, Iceland, Great...

.

Rhodiola is a genus of perennial plant

Perennial plant

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

s in the family Crassulaceae

Crassulaceae

Crassulaceae, or the orpine family, are a family of dicotyledons. They store water in their succulent leaves. They are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce...

 that resemble Sedum

Sedum

Sedum is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. It contains around 400 species of leaf succulents that are found throughout the Northern Hemisphere, varying from annual and creeping herbs to shrubs. The plants have...

 and other members of the family. Like sedums, Rhodiola species are often called stonecrops. Some authors merge Rhodiola into Sedum.

Rhodiola species grow in high-altitude and other cold regions of the Northern Hemisphere

Northern Hemisphere

The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

. Den virtuella floran gives the number of species as 36, the Angiosperm Phylogeny Group

Angiosperm Phylogeny Group

The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants that would reflect new knowledge about plant relationships discovered through phylogenetic studies., three...

 gives it as 60, and the Flora of China

Flora of China (journal)

Flora of China is a scientific publication aimed at describing the plants native to China.The is a collaborative scientific effort to publish the first modern English-language account of the approximately 31,000 species of vascular plants of China...

 gives it as about 90, with 55 in China and 16 endemic there. The USDA Plants database lists only 3 species in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

.

Among the distinguishing characters of the genus are two series of stamen

Stamen

The stamen is the pollen producing reproductive organ of a flower...

s totaling twice the number of petal

Petal

Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...

s; free or nearly free petals (not joined in a tube); a stout rhizome

Rhizome

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

 from whose axils the flowering stems rise; and a basal rosette

Rosette (botany)

In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...

 of leaves. This genus contains the only species of Crassulaceae that have unisexual flowers.

The Holarctic

Holarctic

The Holarctic ecozone refers to the habitats found throughout the northern continents of the world as a whole. This region is divided into the Palearctic, consisting of Northern Africa and all of Eurasia, with the exception of Southeast Asia and the Indian subcontinent, and the Nearctic,...

 species Rhodiola rosea

Rhodiola rosea

Rhodiola rosea is a plant in the Crassulaceae family that grows in cold regions of the world. These include much of the Arctic, the mountains of Central Asia, the Rocky Mountains, and mountainous parts of Europe, such as the Alps, Pyrenees, Carpathian Mountains, Scandinavia, Iceland, Great...

 is used in herbal medicine. A number of species are grown as ornamentals, but growing them is difficult outside their native subarctic and alpine climates.

The name combines the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 rhodon, meaning rose

Rose

A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles. Flowers are large and showy, in colours ranging from white through yellows...

 and referring to the rose-like smell of the roots, with the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 diminutive

Diminutive

In language structure, a diminutive, or diminutive form , is a formation of a word used to convey a slight degree of the root meaning, smallness of the object or quality named, encapsulation, intimacy, or endearment...

 suffix -iola.

Species include:

• Rhodiola integrifolia
  Rhodiola integrifolia
  Rhodiola integrifolia is a species of flowering plant in the stonecrop family known by the common names western roseroot, king's crown, and ledge stonecrop. It is native to Eurasia and western North America, where it grows in mountainous habitat in subalpine and alpine climates, including meadows,...
  
  
• Rhodiola rhodantha